REPLACEMENT GEARBOXES and GEARS available From Loco Doc
GEARBOXES FOR 3MM AXLES (USED ON ALMOST ALL HO BRASS)
| BRAND | PSC | PSC | PSC | PSC | NWSL | NWSL | NWSL | NWSL | NWSL | NWSL | NWSL |
| PART # | 4018 | 4018.1 | 4018.13 | 4018.12 | 140-6 | 139-6 | 136-6 | 151-6 | 150-6 | 241-6 | 240-6 |
| RATIO | 27/1 | 36/1 | 27/1 | 27/1 | 27/1 | 27/1 | 27/1 | 36/1 | 36/1 | 28/1 | 28/1 |
| #OF IDLERS | 1 | 1 | 0 | 1 | 0 | 1 | 2 | 0 | 1 | 0 | 1 |
| WORM OFFSET | .775" | .860" | .310" | .710" | .256" | .591" | .925" | .303" | .732" | .323" | .78" |
| CASE | METAL | METAL | PLAST | PLAST | PLAST | PLAST | PLAST | PLAST | PLAST | PLAST | PLAST |
| Min.Driver" | 49-40" | 62-54" | 40-30" | 40-30" | 46-33" | 46-33" | 40-33" | 56-40" | 56-40" | 58-43" | 58-43" |
| OPTIONS | A | B | W | N,X | O,W | P,W | P,X | Q| Q,X |
| ||
| PRICE | $16.50 | $17.25 | $12.25 | $16.50 | $24.95 | $29.95 | $31.95 | $24.95 | $29.95 | $24.95 | $29.95 |
Minimum Driver Diameter; First # is with gearbox cover, Second # is with gear exposed.
OPTIONS;
A. Available for articulateds as a "high low" gearbox set as #4018.6
at $29.75.
B. Available for articulateds as a "high-low" gearbox set as #4018.14
at $29.75.
N. Available
for articulateds as a "high-low" gearbox set as#148-6 $37.95
P.
Available for articulateds as a "high-low" gearbox set as#158-6 $39.95
Q. Available for articulateds as a "high-low" gearbox set as#247-6
$39.95
W.Convertable to 2mm worm shaft (part # 144-6 ), for 1.5mm
worm shaft order part #145-6 Price for either $6.00
X. Convertable to 2mm worm shaft (part #164-6), for 1.5mm worm shaft order part #165-6 price for either
$6.00
COMMENTS;
The PSC gearboxes are my current favorite because they have spherical bronze worm shaft bearings and assemble easily. Current production of #4018 and #4018.1 (painted black) are Korean made and not the same or as good as the older KTM made boxes (silver metal color) of Westside days. I will buy any of the old ones.
When building the NWSL gearboxes it is important for the worm shaft bearings to be perfectly inline, if not the bearings will bind on the shaft and overload the motor. When I assemble NWSL gearboxes, I chamfer the inner and outer surfaces of the gearbox halves where they touch the wormshaft bearings. Thus only a small ring of the gearbox clamps the bearing and the bearings can allign themselves on the shaft allowing free and smooth rotation of the driveshaft.
POLISHED STEEL WORMS TO REPLACE WORN AND DEFECTIVE GEARS
The worm is the most easily damaged gear and will destroy the gear it drives
if it has a rough tooth surface or if it is damaged. The worm MUST be made of
a discimilar and harder material than the gear it drives. Poor quality, worn
or soft brass worms should be replaced before they damage other gears.
I always replace any brass worm with a NWSL polished steel
worm. It is a very cheap investment in longer gear life. Always check a Nakamura
HOn3 loco for brass idler gears as I have also found brass idler gears in a modern
slide valve K-27 and an American Garrett, engines built well after Nakamura
started using the nylon idler gears.A Standard worm has threads running like a
screw or bolt and runs foreward turning clockwise. A reverse worm is opposite.
REPLACEMENT STEEL WORMS
| DESCRIPTION | NWSL | NWSL | NWSL | NWSL | NWSL | NWSL |
| GEAR PITCH | 3MOD | 3MOD | 72DP-3.5MOD | 72DP-3.5MOD | 4MOD | 4MOD |
| GEAR CUT | STD.WORM | REV.WORM | STD.WORM | REV.WORM | STD.WORM | REV.WORM |
| GEAR O.D. | 5MM | 5MM | 4.8MM | 4.8MM | 6MM | 6MM |
| 1.2MM SHAFT | 10800-6x + | 10801-6 + | 50800-6 + | |||
| 1.5MM SHAFT | 1313-6 ^ | 1335-6 ^ | 10400-6 x | 10401-6 x | ||
| 2.OMM SHAFT | 1312-6 ^ | 1334-6 ^ | 10500-6 x | 10501-6 x | 50500-6 + | |
| 2.4MM SHAFT | 230600-6 - | 230601-6 ^ | 10000-6 0 | 10001-6 x | 50600-6 - | 50601-6 - |
DELRIN IDLER GEAR UPGRADES FOR WESTSIDE HOn3 LOCOMOTIVES
Quite a few very good HOn3 locomotives built
by Nakamura were produced with a brass worm driving brass idler gears
rotating on 3mm brass shafts. A rule of gear design is that the worm and pivot shaft
must be made of a harder and discimilar material than the "worm gear"
it drives. All these locomotives ( Lambert C&S 2-6-0 , Westside C-25,
K-37, compound K-27, original slide valve K-27 and possibly others ) should
have their idler gears replaced with delrin idler gears.
If the shaft is worn or if you want a quieter, smoother
and lower friction drive that also increases flywheel coast, LocoDoc has developed a
custom NWSL made 26 tooth delrin
idler gear mounted on a 1.5mm hardened steel shaft. It also includes two custom
brass bearings to fit the shaft and center the gear in the gearbox. This is a big
improvement over the NWSL 305-6 gear below.
LocoDoc #305 gear upgrade $20
If your pivot shaft is not damaged; we offer NWSL Delrin idler gear #305-6 Price $6.95 that mounts on the original large pivot shaft.
KEY MODELS
Several models built by Samhongsa had brass idler gears which tend to be noisy and wear out and several rotate on brass sholdered screws, a short lived design. The following delrin idler gears are custom made by us using NWSL gear stock.
LocoDoc C&S #22 2-6-0
$20
LocoDoc C&S #58 2-8-0 (also #60, #65 & #69) $20
LocoDoc RGS #42 2-8-0 (also C&S #71) $20
Go to ORDER FORM
Return to ROUNDBELL HOME PAGE
Return to LOCO DOC HOME PAGE